Process of tanning hides and skins



- This invention relax tann Patented July 21, 1942 V y =s el; se sjnssm.sitssi mssms' 4 1 Carl1-"Ri'ess,"-- Ludwigshafen-on-the Rhine,"and

' 'ltudolf WatzeL-Mannheim, Germany, assi'gnors. to Chemische FabrikJoh. Benckiser G; m.

b..--H., :Ludwigsh-afen-on-the-Rhine, Germany;

.a,corp oration of Germany c na-nag; Application'April 19,1940, Serialstances containing col-l'agen,-and' is'more-particu- 'larlyircted"to"compositions"and processes-for g wherein a fr'eaction"producto'f rnolecu-v larlydehydi atedpolymeric phosphoric acids andaromatic"'hydr'oxycompouncls employed; "the latter having beforebeenreactedwithnucleus bmsin a'g'ents; i "'It is-well'known to use inthe'"tan"ning"o'f leathers and furs molecularly dehydratedl polymericphosphoricacids and their salts for tan- "ning,-pretanning*orretanning.j V V We have:foundfthatsuperior tanningjefiects can be obtained,"wnenusing reaction products of molecuiarly dehydrated polymeric'phosphoricacids" with aromatic hydroxycompounds, "the latter having before beenreaCted With nucleusbinding substances, such as sulphuric'acid'and/oraldehydes; 1 If Among the suitable "aromatic'fhydroxy'com- 'poundsth'ose of first importance are: phenols,

cresols, naphthols, "their' substitution products,

- and analogous-compounds. These agents are first reacted withnucleus-binding substances, such as sulphuric acid, chlorosulphonicacid, aldehydes, or mixtures thereof, processesfrom'which result asintermediary composit ons polynuclear,

not condensed systems, linked'to 'each other by SO2,-CH2 or analogousgroups, such as 'dihydroxy-diphenyl-sulphorie, dihydroxydinaphthylsulphone, dihydroxydiphenyl-methane v The process of thepresent invention"'begins' with the preparation of the 'polynucleararomatic hydroxycompounds by hea.ing the hyd'r'oxycompounds; forexample'phenols, with nucleus binding substancesf for example sulphuricacid or formaldehyde,- anddressing in known manner.

The resulting products are how. brought 'to" re action with molecularlyanhydrous polymeric phosphoric "acid, both components 'having'beforebeen heated to 200 .or 300 C. Molecularly'anhydrousor dehydratedpolymeric phosphoric acids include all polyme"ic phosphoric acidscontaining a lesser ,quantity of molecularly bound water thanorthophosphoric acid. Among such acids, those of first importancearepyrophosphoric acid and the different polymeric metaphosphoric acids,such as di-, tri-, tetra-,- hexa-, meta-phosphoric acids, etc. of thegeneral formula (HPOQn. Such molecularly anhydrous polymeric phosphoricacids also include other so-called polymeric phosphoric acids, such aspolymeric triphosphoric acid, polymeric tetran 330,560.; In GermanyApril'lfi, 1939 gamma (cunt-,5) generally to the tanning V I der 'An organischen Chemic, 8th, edition, volume 2 of --hides, 'kips;slriiisfiinciother organic sub The tanning e'fie'ctpj the new jproductsis considerably-superior to that of simplev anhydrouspolymericfphosphorlc acids or their salts. In a,

comparison 'with'other synthetic tanning fsub stances o;high'nioleculafweight theyfhave the advantage of being verystable'andnearly odourless, 10

n'd of[bein gj easily waterjss'oluble in any concentration. i

Ea;ample 1. 250 g. of "the ireaictionh'idduct fo med jheaunizjemmjgmoiecuies of phenol j and jfl gram-molecule of sulphuric facid totemperatures, b'eyond 1 Cgand consisting inthe inain' part ofhydroxy-diphenybsulphone are neutralized. V

Example 29 200 g. of the product of condensat'ion ofjzY igm-molecuies.of phenol and 1 grani molecule of formalqehyde. consisting in the" mainpart 'of. fhydroxy;diphenyhmethane,

are "molten with 200' 'g', of anhydrous phosphoric acid' as in Example"'1, and neutralized I after cooling.

a aste forml or execution ofathe present process is to react uithformaldehyde the products formed by reaction of anhydrous polymericphosphoric acid 'With] aromatic hydroxycom pounds By'thisstepaiurthercondensation or "accordingJto'Example lor I Ipolymerization; still increasing. and intensifying the nni g eifect ofthejpresentlproducts, is

"'supposed'totakeplace. v EJZQZMPZG Br TO the productprepared accordingto Example 1 or 2 arefadded after cooling} but before neutralizing, 40to jg. of 40%-- formaldehyde solution. The mass is then. heated untildisappearance "ofthe formaldehydeodour, cooled, and'ne'utralized; Theproducts thus pre-' pared have higher tanning qualitiesthan those WhatWe claim is f 1. In a process of tanning hides, skins and the like, thestep comprising subjecting. the material to a tanning solutioncontaining a product formed by reaction of molecularly dehydrated.polymeric phosphoric acid with a product of the,

hydroxycompounds condensation of aromatic and nucleus-binding agents.

2. In a process of tanning hides, skins and the like, the stepcomprising subjecting the material to a tanning solution containing aproduct formed by the reaction of. molecularly dehydrated phosphoricacid, etc. (See Gmelin Handbuch I polymeric phosphoric acid with aproduct of con

